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Diseases of Internal Combustion Engines

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DISEASES OF INTERNAL COMBUSTION ENGINES An internal combustion engine of whatever kind or make is very like a human being, in that if it isn't looked after and treated well it will be sure to develop some disease, and so go into an early decline; and sometimes, too, exactly like the mechan ism of a man, it will ail and growl around when there isn't a thing on earth the matter with it.

In the foregoing chapter I mentioned that there are three general symptoms by which you can tell when something has gone wrong with your engine, but what I did not tell you was that each symptom may indicate any one of a dozen different troubles, and to find the offending one you must know the specific symptoms of it.

Now, while it might seem on the face of it to be a pretty hard matter to locate the fault, since there are so many of them—fixing it is easy when you know what to fix—it is not at all a hard job if you go about it the right way, and this is by the process of When the Engine Works Badly.—The Seat of the Trouble.—When the engine works poorly it may be caused by (1) a priming cock that leaks; (2) poor compression caused by a loose or a broken spark plug; (3) or trouble with the ignition system; (4) gaskets that leak; (5) the use of lubricating oil that has too light a body; (6) piston rings that give too much clearance; (7) piston rings that are bent or are otherwise faulty; (8) a broken lockpin in the piston ring, or (9) valves that do not seat properly.

Finding and Fixing the order I have given above is the one in which you should look for the fault and after testing each one out thoroughly see if the engine works all right or not.

Begin, then, by looking after (1) the priming cocks; if the leak is bad the sound of escaping gases around the loose one will indicate it clearly enough; if there is no sound, squirt a little oil on it where it screws into the cylinder head, and if it leaks little bubbles will rise in the oil.

To fix it try tightening the cock up with a wrench and if you can't get it tight enough to keep it from leaking put a little red-lead on the threads and then screw it up. (2) Sometimes a spark-plug gets a lit tle loose or the threads are worn. To find out

whether it leaks squirt a little oil around the threads and watch for the bubbles as explained above. Tight en it up and use some red-lead on the threads if necessary. If the spark-plug is cracked there will be a considerable loss of compression through it and when this happens you can hear it wheeze, and to fix it all you have to do is to put in a new plug.

(3) When there is no leakage from the spark-plugs or gaskets and the compression seems to be good, ex amine the ignition system very carefully and look particularly for a loose wire or a grounded wire, by which I mean a wire that has worked loose in its binding post or one whose insulation has been rubbed off and so mixkes a slight contact with some other wire or with the engine itself. When you have at tended to these details the chances are that your en gine will rim as well as it did when you bought it, provided you bought a new one.

(4) If the gaskets leak you will know it by the wheezing sounds of the exhaust gases. It may be that the nuts are loose and tightening them will do the business, but do this while the engine is hot.

Should the gaskets be worn out or rotted out, cut new ones out of asbestos packing 1 which has a brass or bronze wire mesh in it. When you put on a new gasket smear both sides of it with linseed or lubricating oil and tighten the bolts up when the engine is hot. (5) The next thing to try is a lubri cating oil having a heavier body than the one you are using; to do this unscrew the drain plug from the crankcase and run out all of the old oil. This done, screw in the plug and fill the crankcase, or sump, below it, whichever it is, to the oil level with kerosene.

Now run the engine slowly for half a minute or so, when it will clean out the working parts of the engine. Take out the drain plug again and run out all of the kerosene, put back the drain plug and fill the crankcase or sump with the heavier grade of lu bricating oil. If nothing else is the matter you will find that your engine will develop more power than you ever gave it credit for.

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